铝合金7A04在干湿周浸条件下的腐蚀行为研究(英文)

采用扫描电镜、X光电子能谱、失重法和电化学交流阻抗技术研究了铝合金7A04在0.6 mol/L NaCl溶液和0.6 mol/LNaCl+0.02mol/L NaHSO3溶液中干湿周浸后的腐蚀行为和规律,并测试了3种材料力学性能的变化.研究结果表明,随试验时间的延长,铝合金腐蚀产物不断增多,腐蚀失重符合指数规律C=A tn,抗拉强度和延伸率呈下降趋势;表面腐蚀产物形貌呈块状,在0.6 mol/L NaCl溶液中腐蚀产物主要为氢氧化铝和氯化铝,而在0.6 mol/LNaCl+0.02 mol/LNaHSO3溶液中腐蚀产物主要为氢氧化铝、氯化铝和硫酸铝.电化学交流阻抗谱显示铝合金7A04在0.6 mol/L NaCI+0.02 mol/0L NaHSO3溶液中的腐蚀速率远大于在0.6 mol/L NaCl溶液的腐蚀速率,并探讨了其腐蚀机理.     

环氧粉末涂层在1.5mol/LNaCl溶液中的失效行为

通过电化学阻抗谱(EIS)对两种环氧粉末涂层在1.5 mol/LNaCl溶液中的失效行为进行了研究,利用扫描电子显微镜(SEM)和能谱仪(EDS)对涂层底部金属表面的腐蚀产物进行了分析,探讨了环氧粉末涂层在1.5 mol/L NaCl溶液中的失效机理。结果表明,在1.5 mol/L NaCl溶液中,Cl-等腐蚀介质能在涂层中形成传输通道渗透到涂层与金属界面,并参与界面的腐蚀反应,腐蚀产物主要为Fe的氧化物和氯化物。     

Na2MoO4-有机膦A复合缓蚀剂对55%LiBr溶液中碳钢的缓蚀行为

采用失重法、电化学测试技术、原子力显微镜和电子探针显微分析等方法考察了Na₂MoO₄-有机膦A复合缓蚀剂对55%LiBr+0.07 mol/L LiOH溶液中碳钢的缓蚀性能。结果表明,240 ℃下碳钢在添加800 mg/L Na₂MoO₄-有机膦A复合缓蚀剂的55%LiBr+0.07 mol/L LiOH溶液中的腐蚀速率为43.2 μma^-1。在沸腾的55%LiBr+0.07 mol/L LiOH溶液中添加该缓蚀剂后,碳钢的钝化电位区间拓宽,钝化电流密度降低,反应电阻R_t值显著增加,缓蚀效率可达94.4%。该缓蚀剂能使碳钢表面形成显微结构为孤岛状的膜层,主要成分为Fe和Mo的氧化物。     

食品包装用镀锡薄钢板的腐蚀机理研究进展

镀锡薄钢板由于高强度、高阻隔性及优越的加工使用性能,在食品包装材料中占有非常重要的地位,当内容物腐蚀性较强时,其缺点之一是会发生腐蚀失效。本文综述了食品环境中镀锡薄钢板的腐蚀行为,探讨了食品包装用镀锡薄钢板和有机涂层涂覆的镀锡薄钢板的腐蚀机理。镀锡薄钢板的腐蚀过程与内容物p H值、溶解氧含量以及腐蚀性离子种类密切相关。可为镀锡薄钢板采取合适的表面处理措施以及设计新型有机涂层材料提供科学依据。     

pH值对马氏体沉淀硬化不锈钢PH13-8Mo腐蚀电化学行为的影响

通过静态浸泡腐蚀实验以及极化曲线测试、电化学阻抗谱测试、Mott-Schottky曲线等电化学测试技术,结合扫描电子显微镜技术研究了马氏体沉淀硬化不锈钢PH13-8Mo在不同pH值的0.5 mol/L的Na_2SO_4溶液中的腐蚀行为。结果表明:PH13-8Mo的耐蚀性随着溶液pH值的升高而增强,不同的pH值影响了腐蚀的速率及腐蚀产物的形貌。随着溶液pH值的升高,腐蚀电流密度Icorr减小,极化电阻Rp增大,容抗弧的幅值增大,钝化膜中缺陷密度降低,钝化膜的致密性增强,耐腐蚀性能提高。     

胡萝卜茎叶提取物对碳钢在0.5 mol/L H2SO4溶液中的缓蚀作用

目的研究胡萝卜茎叶提取物(DCSLE)在硫酸介质中对碳钢的腐蚀抑制作用及机理。方法通过超声辅助的手段,用水浸提获得DCSLE,利用红外光谱(FTIR)对其含有的主要官能团进行表征。在25~40℃下,采用失重法、电化学极化和阻抗法(EIS)评价DCSLE在0.5 mol/L H2SO4溶液中对碳钢的缓蚀性能,并讨论了其缓蚀机理。结果DCSLE对碳钢在0.5mol/LH2SO4溶液中的腐蚀具有良好的抑制效果,其缓蚀效率随浓度的增加而增加,随温度的增加而先增加后降低(40℃<25℃<30℃<35℃),35℃下,质量浓度为0.6g/L时,缓蚀效率为92.85%。电化学测试表明,DCSLE是混合型缓蚀剂,但主要是抑制阴极的反应。其缓蚀机理是:DCSLE以物理和化学混合吸附的方式吸附在碳钢表面,形成一层保护膜,从而阻止酸溶液的侵蚀,且吸附遵循Langmuir吸附等温模型。扫描电镜(SEM)观察到加入DCSLE后,碳钢的腐蚀得到了明显控制。结论DCSLE可以有效抑制碳钢在0.5mol/LH2SO4溶液介质中的腐蚀,是一种具有广泛应用前景的天然绿色缓蚀剂。     

3.5%NaCl溶液中Ni-Co镀层失效过程的EIS研究

采用电化学阻抗谱(EIS)技术对电沉积Ni-Co镀层在3.5%NaCl溶液中的腐蚀失效过程进行了研究,发现可采用4种等效电路对镀层的失效过程进行拟合:浸泡初期,镀层耐蚀性能良好,可以简单的等效为镀层电阻与镀层电容的并联;浸泡一段时间后,镀层/金属界面上发生腐蚀反应,引入了双电层电容和界面电荷转移电阻;浸泡后期,界面上的腐蚀产物产生积累,引入反映腐蚀产物信息的Warburg电阻元件;当腐蚀产物的积累影响到腐蚀介质的扩散时,引入了扩散电阻和扩散电容。通过对失效过程中镀层电阻和电容随时间的变化曲线进行分析,发现Ni-Co镀层在3.5%NaCl溶液中的失效过程可分为3个阶段:腐蚀介质的渗透阶段,界面金属的腐蚀阶段和镀层的失效阶段。     

Na_2SO_4水溶液中Mg-10Gd-2Y-0.5Zr微晶薄膜的电化学腐蚀行为

利用磁控溅射技术制备了晶粒尺寸为300nm～400 nm的GW102K(Mg-10Gd-2Y-0.5Zr)微晶薄膜.通过动电位极化曲线和电化学阻抗谱(EIS)研究微晶薄膜在0.2 mol/L Na_2SO_4水溶液中的腐蚀行为.极化曲线结果表明,微晶化加速GW102K靶材合金的阴极过程,而抑制其阳极过程.EIS结果表明,微晶化降低GW102K靶材合金在自腐蚀电位下的转移电阻和腐蚀产物膜电阻,从而降低其耐蚀性.微晶化提供大量的晶粒边界,氢原子通过晶粒边界快速扩散,生成氢化物,从而加速GW102K靶材合金的阴极反应速率.此外,微晶化促进金属的阳极溶解,使微晶薄膜表面形成大量均匀的腐蚀产物,从而抑制金属的进一步溶解.     

含稀土HAl77-2铝黄铜的腐蚀行为

通过测定3种不同成分的铝黄铜在NaCl（3.5%）溶液和NaCl（3.5%）＋NH4Cl（0.5 mol/L）溶液中的腐蚀速率、电化学行为分析,以及对腐蚀产物层进行SEM观察和XRD分析,研究了铝黄铜的腐蚀行为。结果表明：添加Ce可以降低铝黄铜在NaCl（3.5%）溶液中极化时的自腐蚀电流密度;含Ce的Cu-Zn-Al-Ni-B-Ce在NaCl（3.5%）溶液中腐蚀后腐蚀产物层表现出最佳的腐蚀形貌和耐腐蚀性能,而添加稀土并不能改善铝黄铜在NaCl（3.5%）＋NH4Cl（0.5 mol/L）溶液中的耐腐蚀性能;联合添加As和Ce的Cu-Zn-Al-Ni-As-B-Ce在这2种介质中的耐腐蚀性能反而下降。     

超音速火焰喷涂镍基合金层的腐蚀失效过程

采用超音速火焰喷涂(HVOF)方法在低碳钢表面制备NiCrBSi合金涂层,利用交流阻抗法(EIS)研究镍基合金层在3．5％NaCl溶液中的腐蚀失效过程。由于喷涂层中存在气体,介质与基底接触前喷涂层的电极电位高于同种材料堆焊层的电位。涂层浸泡初期,孔隙等缺陷的存在破坏了涂层金属表面吸附层的完整性。随着腐蚀介质在涂层中进行渗透,腐蚀集中在孔隙等局部区域进行。最后,介质通过涂层渗达涂层／基底界面,碳钢作阳极遭受腐蚀。馀层的耐蚀性在浸泡初期急剧降低,后因腐蚀产物阻塞孔隙等腐蚀通道而有所上升。腐蚀介质接触碳钢基底后,复合电极的耐蚀性继续下降。     

超音速火焰喷涂FeCrSiB涂层的腐蚀行为

采用超音速火焰(high velocity oxygen fuel,HVOF)喷涂技术在Q235钢基体上制备了FeCrSiB合金涂层.利用X射线衍射仪、扫描电子显微镜、电化学工作站等设备对涂层的显微组织结构和耐腐蚀性进行了研究.结果表明,采用HVOF喷涂技术制备的FeCrSiB涂层结构致密,孔隙率为0.65%,与基体结合良好.FeCrSiB涂层在3.5%NaCl溶液、1 mol/L HCl溶液和1 mol/L NaOH溶液中都经历了活性溶解-钝化-过钝化的过程,且该涂层在3.5%NaCl溶液和1 mol/L HCl溶液中的耐腐蚀性能要优于镀铬层,在1 mol/L NaOH溶液中的耐腐蚀性能低于镀铬层.     

Improvement in corrosion resistance of magnesium coating with cerium treatment

Corrosion protection afforded by a magnesium coating treated in cerium salt solution on steel substrate was investigated using open circuit potential, polarization curves, and electrochemical impedance spectroscopy (EIS) in 0.005 M sodium chloride solution (NaCl). The morphology of the surface was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The cerium treated coating was obtained by immersion in CeCl3 solution. The results showed that the corrosion resistance of the treated magnesium coating was improved. The corrosion potential of the treated coating was found to be nobler than that of the untreated magnesium coating and the corrosion current decreased significantly. Impedance results showed that the cerium treatment increased corrosion protection. The improvement of anti-corrosion properties was ataibuted to the formation of cerium oxides and hydroxides that gave to a physical barrier effect.     

Primary investigation of corrosion resistance of Ni-P/TiO2 composite film on sintered NdFeB permanent magnet

In this paper, an electroless nickel plating and sol-gel combined technique used to prepare the Ni-P/TiO₂ composite film on sintered NdFeB permanent magnet is described and the composite film was characterized by X-ray diffraction (XRD), environmental scanning electron microscopy (ESEM), and energy dispersive X-ray spectrometer (EDX). The corrosion resistance of Ni-P/TiO₂ film was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The self-corrosion current density (i_corr) of Ni-P/TiO₂ composite film is 2.38μA/cm² in 0.5mol/L H₂SO₄ solution about 33% of that of Ni-P coating and 0.22μA/cm² in 0.5mol/L NaCl solution about 14% of that of Ni-P coating, respectively. In 0.5mol/L H₂SO₄ and 0.5mol/L NaCl solutions, the polarization resistance (Rp) of the composite film is 12.5kΩ cm² and 120kΩ cm², about 1.6 and 2 times that of Ni-P coating, respectively. The results indicate that Ni-P/TiO₂ composite film has a better corrosion resistance than Ni-P coating.     

碳钢表面电镀Ni-TiO2镀层硬脂酸修饰制备超疏水表面

目的 在碳钢基体上制备超疏水表面,提高碳钢的耐海水腐蚀性能。方法 采用恒电流沉积结合硬脂酸修饰的方法,在碳钢表面制备超疏水Ni-TiO2复合镀层。通过扫描电子显微镜（SEM）、EDS能谱分析、傅里叶红外光谱仪（FTIR）、X射线衍射仪（XRD）,对样品的形貌、化学组成及晶型结构进行分析。通过接触角测量仪、自清洁测试,对试样的表面润湿性及自清洁性进行分析。利用电化学工作站测量样品的电化学阻抗谱和极化曲线,从而对样品的耐蚀性进行评价。结果 制备的Ni-TiO2复合镀层呈球形微纳米粗糙结构。经硬脂酸修饰后,接触角高达160.99°,具有良好的超疏水性和自清洁性能。制备的超疏水Ni-TiO2复合镀层在3.5%NaCl溶液中的自腐蚀电流密度为2.42×10-8 A/cm2,腐蚀速率为2.84×10-4 mm/a,对裸碳钢的缓蚀效率为99.41%,具有优异的腐蚀保护作用。此外,在3.5%NaCl溶液中浸泡60天后,超疏水Ni-TiO2复合镀层的电荷转移电阻Rct变化很小,镀层没有破损,具有长期防腐蚀性能。结论 在碳钢表面通过恒电流电沉积结合硬脂酸修饰制备的超疏水表面,能长期有效地提高碳钢对海水的耐腐蚀性能。     

Corrosion protection properties of cerium layers formed on tinplate

Corrosion protection properties of cerium-passivated, unpassivated and chromium-passivated tinplates in contact with a 0.1 M citric-citrate buffer solution were studied using polarisation (DC) and electrochemical impedance spectroscopy (EIS) methods. The morphology and composition of the passive layer were studied using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS) in conjunction with argon-ion sputtering. Cerium-passivated tinplate showed similar corrosion properties to chromium-passivated tinplate in DC measurements, while the latter yielded the best corrosion resistance results in EIS measurements. SEM and EDX illustrated spherical particles with iron, cerium and tin contributions. XPS measurements indicated that the cerium-rich coating was a hydrated oxide with a composition of cerium(III): Ce(OH)₃ and cerium(IV): CeO₂ and Ce(OH)₄.     

EIS STUDY ON THE EFFECTS OF HEAT TREATMENT ON CORROSION BEHAVIOR OF NICKEL BASE ALLOY COATING

采用超音速火焰喷涂(HVOF)方法在碳钢基体上制备了NiCrBSi喷涂层, 对包覆样 品进行900 ℃保温2 h或10 min热处理, 利用电化学阻抗谱(EIS)研究了涂层在3.5%NaCl 水溶液中的腐蚀失效过程和耐蚀性的变化规律. EIS图谱分析表明, 喷态涂层抗介质渗透能力 差, 腐蚀20 h后介质可渗达碳钢基体;900 ℃, 2 h保温热处理涂层腐蚀 15 h后EIS谱发生明 显变化, 产生局部腐蚀;而900 ℃, 10 min处理涂层为均匀腐蚀, EIS谱形可长时间保持稳定. 利用等效电路拟合, 获取了涂层界面反应阻力(腐蚀抗力)随时间变化的关系, 显示高温短 时(10 min)热处理涂层的界面反应阻力高且稳定, 其耐蚀性和抗介质渗透能力远优于喷态 涂层, 但2 h保温热处理涂层的耐蚀性比喷态涂层的差. 利用组织结构分析解释了热处理影响 涂层腐蚀行为的原因.     

Wear and corrosion studies of Fe–B–Cr alloy coating on en 24 steel by HVOF thermal spray method

This work investigate the wear behavior of Fe–B–Cr coatings on medium carbon steel (EN24) substrate is used for several automotive parts. The high velocity oxy-fuel (HVOF) method was used to create the new crystalline coating of Fe–B–Cr (composition of 59%Fe–26%B–15%Cr in wt %) on a medium carbon steel substrate (AISI 4340). The characteristics of powder and coating are investigated using scanning electron microscopy (SEM) merged with energy dispersive spectroscopy (EDS), optical microscopy (OM) and thermogravmentric analysis (TGA) which were undertaken in the partial characterization of the coating. The phase contents of both powder and coatings were studied by X-ray diffraction (XRD). The coatings consist of melted and un-melted particles identified in the coatings. Moreover, oxides and micro-cracks were observed at the surface. The mechanical property of the coatings was characterized using a microhardness test. The hardness value increased three times more than the substrate. The coated surface showed lower levels of porosity. Moreover, the electrochemical investigation found Fe–B–Cr coating on medium carbon steel. The corrosion test was carried out in an environment with 0.5 M of NaCl, which showed that the corrosion resistance improved by coating.     

X80管线钢埋弧焊焊接接头的组织和腐蚀性能

采用H08MnMoA焊丝埋弧焊焊接X80管线钢.利用扫描电镜分析焊接接头微观组织;采用动电位极化和电化学阻抗法研究了X80管线钢其焊接接头在0.5 mol/LNaHCO3+0.02 mol/L NaCl溶液中的腐蚀行为.结果表明,在0.5 mol/L NaHCO3+0.02mol/L NaCl溶液中,由于显微组织上的差...     

The effect of processing gas on corrosion performance of electroless Ni-W-P coatings treated by laser

An investigation of the microstructural and corrosion characteristics of electroless Ni-5.5 W-6.5P coatings on steel substrates after laser treatment in argon and air is presented. The microstructural characteristics of the coatings, in terms of crystallisation, grain size, microstrain, porosity as well as surface chemistry, were examined using quantitative X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical tests, using potentiodynamic polarisation in 0.5 M H₂SO₄ solution and electrochemical impedances spectroscopy (EIS) in 3.5% NaCl solution, were undertaken to evaluate the corrosion behaviour of the coatings. The results indicated that the laser-treated coatings consisted of nanocrystalline Ni and Ni₃P phases, along with retained amorphous phase; further, the dimensions of the Ni crystallites were larger than those of Ni₃P. The laser-treated coating in argon revealed the presence of submicron scale porosity, while no porosity was evident in the coating surface treated by laser in air. The uniform corrosion revealed in 0.5 M H₂SO₄ solution is mainly determined by the microstructural characteristics of the coating. Pitting corrosion in 3.5% NaCl solution depended on the amount of porosity on the surface. The laser-treated coating in air exhibited better corrosion resistance in both acidic and chloride environments than that laser-treated in argon.